Document DDwDqVYRMojx0JrRNaNJnBwqd

American Society of Heating and Ventilating Engineers Guide, 1929 Table 4. Apartment Houses. Sues of Water Supply Mains* and Meters Based upon pressure drop of 10 lb. per 100 ft. run For 4 and S Stories Apartments per Floor 1 bath. ........... 2 baths..-.... ..... 3 baths. Fora GaL Main 120 2)4' 160 3' 200 3" Six GaL Main 160 3' 200 3' 240 3' Eight GaL Main 200 3' 240 3' 280 3' Tex Gal. Main 240 3' 280 3' 320 3)4' For 6, 7 and 8 Stories 1 bath______ _ 2 baths._______ 3 baths. 150 190 230 2M" 3' 3* 190 230 270 3* 3' 3' 230 3' 270 3' 270 3' 310 3)4' 310 3)4' 350 3)4' For 9, 10,11 and 12 Stories 1 bath_________ 200 3' 250 3' 300 3)4' 350 2 baths. _____ 250 3' 300 3)4' 350 3)4' 400 3 baths..______ 300 ` 3)4' 350 3)4' 400 3)4' 450 Note.--The gallons per. minute given above are approximated maximum demand for conditions stated. Table 4 gives the. sixes of mains for apartment houses of one, two or three baths for each apart ment, and with four, six, eight or ten apartments per floor and from four to twelve stories in height. Example.--What is the required size of water main for apartment house eight stories high, six apartments per floor, each having three baths? Answer from Table 4 is 3 in. Example.--What is the required size of main for a ten-story apartment house with six apartments per floor, each having two baths? Answer from Table 4 is 3) in. main. Table 5. Pipes may be Sized for Giving any Desired Pressure Drop per 100 Ft. of Run Friction Pressure Drop Lb. per Sq. In. per 100 Ft. Run. H 5. 7 10 20 30 40 50 75 100 125 150 . 5.4 6.4 7.6 10.8 13.2 15.0 17.0 21.0 24.0 27.0 30.0 Pipe Sizes in Inches 1 1H 1M 2 2H 3 3K 4- Gallons.per Minute 11 19 30 13 23 36 15 27 43 22 38 61 27 47 ' 76 31 54 86 35 60 66 43 -74. 117. 49 85 136 55 96 .152 60 . 105 166 62. 74 88 125 153 176 197 242 278 311 341 109 171 129 203 154 242 218 343 267 420 308 . 485 345 542 423 665 485 766 544 858 598 939 252 298 357 504 618 714 800 978 1130 1260 1380 353 418 499 ; 706 864 .998! 1115 1365 1578 1765 1930 338 XX--Chapter Water Supply Systems and Piping for Buildings Table 6. Showing Water Pressure Required to Deliver Water to Top of Vertical Riser with. 15 Lb. Pressure at the Top Branch and to Give Adequate Service at Vertical Heights Given Water Pressure in Lb. Required to Deliver Water to Top of Riser with 15 Lb. Terminal Pressure Pressure Drop per 100 Ft. 51b. 15 20.5 25 29.5 35 39.5 44 49.5 54 58.5 64 68.5 73 77.5 83 87.5 7 lb. 15 20.7 25.4 30.1 35.8 40.5 45.2 50.9 55.6 60.3 66 70.7 75.4 80.1 85.9 90.5 10 lb. 15. 21 26 31 37 42 47 53 58 63 69 74 79 84 90 95 201b. 15 22 28 34 41 47 53 60 64 72 79 85 91 97 104 110 Static Heap in Lb. 0 4.33 8.66 12.99 17.32 21.65 25.99 30.32 34.65 38.98 43.31 47.64 51.97 50.30 60.63 64.96 Vertical Rise op Water from Main to Highest Fixture Branch 0 10 20 30 .40 50 60 70 80 90 100 110 120 130 140 150 Water Pressure in Lb. Required to Give Adequate Service at Vertical Heights Given Horizontal Run from Supply to Riser 25' 0" 50' 0" 75' O'' 100' 0" 22.8 lb. 28.1 8 33.5 8 38.8 8 44.1 * 49.5 * 54.8 8 60.1 * 65.2 * 70.8 8 76.1 8 81.5 8 80.8 8 92.1 8 97.5 * 25.3 lb. 30.6 * 36 8 41.3 * 46.6 * 52 * 57.3 862.6 * 67.7 73.3 8 78.6 8 84 * 89.3 94.6 8 100 27.8 lb. 33.1 38.5 8 43.8 8 49.1 * 54.5 * 59.8 8 65.1 * 70.2 * 75.8 * 81.1 8 86.5 8 91.8 8 97.1 8 102.5 * 30.3 lb. 35.0 8 41 8 46.3 8 51.6 * 57 8 62.3 8 67.6 8 72.7 8 78.3 8 83.6 8 89 8 94.3 8 99.6 8 105 8 *Ttfe water pressures given in above table are the pressures at the base of the riser, necessary to deliver water to top of riser with a terminal pressure of 15 lb. when discharging the number of gallons per minute called for in Table 5, at the pressure drop indicated. **Based uDon 10 lb. pressure drop per 100 ft. run of pipe and a terminal pressure of 15 lb. at the uppermost fixture. A terminal pressure of 15 lb. has been selected for operation of flush valves. For terminal pressure of 10 lb., deduct 5 lb. from the figures given above; or for a terminal pressure of 5 lb. deduct 10 lb. from above values. Example.--What are the sizes required for mains and branches in.a building 100 ft. high, supplied with a water pressure of.75 lb. per square inch with 100 gal. of water per minute required on each floor? This is worked out in Table 2 and gives the pipe sizes for the main riser with a 10 lb. drop for 100 ft. of run and shows that a 3 in. main, reduced to 2 in., would be required: branches to the various groups of fixtures can be taken from Tables 5 and 6. On the top floor it will be necessary to use a 1H in. branch to carry 60 gal. per minute with a pressure drop of 30 lb. but that at 30 ft. vertically from the supply, a 1)4 in- branch pipe will carry 60 gal. per minute, therefore 1)4 in. pipe could be selected for this branch. Assuming that the pressure drop in the main riser is 10 lb. per 100 ft. run and the pressure drop on the top floor in the branch does not exceed 15 lb. in all and the static head .for building 100 ft. as given in column 2 of Table 6 is 43.31 lb. making a total of 58.31'lb.; it will be seen that 75 lb.--58.31 lb., which equals 16.59 lb., is the amount of pressure over and above that required, and that this pressure can be utilized to overcome the friction drop in the main feed line running from the source of supply to the base of the riser. FromTable2it is found that 240 gal. per minute will flow at the first floor, and assuming that this water supply is to be brought in a main 300 ft. long; Table 5 will show that a 3)4 in. supply would be necessary. Example.--What pressure is required in the water supply main to give 15 lb. pressure at the uppermost fixture in a building where the riser is 100 ft. high and is located 75 ft. from the water main in a horizontal direction, when the other fixtures within the building are in use to their estimated average capacity? Answer is found to be 75.8 lb. at the intersection of 100 ft. vertical height and 75 ft. horizontal run. Note.--If only 10 lb. be required at the uppermost fixture, then 70.8 lb. would be the answer. WHEN TANK IS ON ROOF If tank is elevated about 35 ft. above highest fixture, which would be about 25 ft. above the roof, similar computations will apply for branch 339